Micro CoGen.

Mike Strizki in New Jersey stores his summer's excess PV energy  via electrolysis of water as low pressure hydrogen in a big tank farm in his yard.  He runs a fuel cell system to generate electricity, which runs a geo source heat pump heating system in winter. 

https://www.scientificamerican.com/article/hydrogen-house/

Payback of never on the electrolyzer and fuel cell system, I expect, but interesting.  PV sized for winter use means gross excess of power, most of the time, and it would be great to be able to put that into long term storage once the batteries are full.  Too bad the cost is out of sight.

It's a pity there's no miniature home power version of the Hall-Héroult process for converting aluminum oxide to aluminum as long term energy storage.  Aluminum is readily converted to heat and hydrogen via lye and water. The waste aluminum oxide could then be converted back to aluminum via PV power.

An interesting project, Veggie.  Since start/stop will be automated, it will be one step beyond my remote start, auto shutdown 6/1.  Howrah!  Looking forward to seeing your progress on this interesting project, Veggie.  I have the Basic code for my Picaxe 40X2 based controller and remote unit, and schematics for the hand wired circuitry if you'd like it.  I'd use an Arduino if stating over today but in truth the PicAxe was/is well suited.

Best Wishes,
Bruce

Hey Veggie,
I think you've got it figured right-  too low delta T with a modest surface area exchange loop.   I'm assuming the engine coolant to solar tank loop is to be pumped or that would be another area where diminished delta T will be a problem.  Pressurizing the engine cooling system and boosting the thermostat comes to mind as one solution in either case, I think.
Bruce

A great tip, Butch, I've printed it from my Lister binder for my next major service.  Thank you!

Cam failures were not uncommonly reported on India twins and some originals.  Do you think that was due to cam shaft warping from cam pin installs with resulting stresses, or some other cause? 

I love this simple fix for the twin dry cam.

A great educational video, a real boon for me on my last engine rebuild.  Thanks Butch!

I'm off grid in central eastern AZ at 5600ft.  Sun is not an issue here, PV is king, but there are plenty of old wind generators out there too, from back when PV was spendy and wind power during winter storms was mighty handy.

I"ve recently looked at converting my 120VDC to lithium NCR20700B cells as my battery bank will need replacing within the next year.  My current (Group 29) wet marine battery bank is 110ah each at 120VDC (10 in series) and costs $900, lasts 4.5-5 years. My DOD is typically 25% in winter, 15% in summer.  A comparable system should have 35AH (minimum usable) at 120VDC nominal.

The NCR20700B cells are rated 4AH but have only 500 cycles of that.  For longer life, you must reduce both high and low ends, so the effective capacity might be 2.5AH.  So being cheap at 14 cells in parallel to barely make 35AH, by 36 cells in series  is $2646. plus shipping at a discounted $5.25 per cell.  This might last 10-12 years, but even at that is still not cost competitive, yet.  (Not counting the new BMS development and construction.) Maybe by my next battery set in another 5 years...  (I've been saying that for 15 years so far.)

I have no use for a big, high current battery charger, in fact, since adding 1500W of PV to my 875W array, I have no need for a charger at all; even on dark winter days I get enough charging, since I avoid all my big loads unless it's sunny or only partially cloudy, in which case the batteries are just a short term buffer.

I do now think that perhaps a well designed, economical, open source PV rack/tracker design would be nice to extend my early morning and late in the day big loads in summer.  The vertical tilt could be manually adjusted monthly.  My ground racks have seasonal tilt only, so mornings and late day are lost in summer  We have very high winds here in spring, thus I have been reluctant to do it.  My ground racks were homebrew from steel square tube and angle and only cost a couple hundred each.  Given the cost and problems here with tracker racks, they mostly have been abandoned by all the PV/off grid contractors and suppliers.  Motors, bushings, bearings etc., all get eaten by the endless AZ dust, and the electronics don't fair that well either.  I may just install another 1500W array mounted on a vertical rack with a pivot pole mount in the middle and a drop bar into concrete on each end to hold it securely.  That could be manually pointed to sunrise or sunset to augment my existing arrays.

I look forward to reading of your fix for the bent camshaft.  Thanks to Butch's great instructional article I was able to address that for my neighbors DES 8/1.  I used hardwood vee blocks and  sledge  hammer with hardwood drift to get it back to true, and the force required was absolutely scary.  I'd find a press if I had to do it again. 

The variable issue with the smaller ST heads and imbalance vibration is clearly related to the utter lack of tolerances and variation of rotors, stators, and windings used, though I have yet to see any ST3 can can be operated split phase.  As I've reported before, with 3 ST-3s in pieces on my bench, no two were alike in stator length.  Centering of the rotor is highly variable and that's rather critical.  In short, they are made much like Listeroids/Clones...buyer beware.  It will be interesting to see if this particular ST-10 can be operated split single phase with moderate load imbalance.  I hope so!

Otherwise, the obvious solution is to use a transformer to generate the 230 or 120V voltage you need the least of.  Antekinc.com is my favorite toroidal transformer supplier; they are typically about 93% efficient and can handle big surge loads (motor start) without a problem.  They are conservatively rated so you needn't allow lots of head room.  Though not ideal, I run 3-800W step down transformers in parallel for my shop 120VAC.   At the time I just couldn't find an affordable 2400W toroid, and I wanted to avoid the inefficiency and large stray magnetic field of a conventional transformer. No problems at 12 years, couple thousand hours of generator/inverter use of those transformers.  I use 2- Antek 1000 W transformers in my 5 step sine inverter and found they are using very efficiency, high inrush current cores; when I switched to them, I had to add a soft start software as I kept blowing fuses and transistors and couldn't figure out why.  I also had to add an inrush current limiting power resistor with timeout bypass relay to to the shop step down transformers for the inverter's sake.  The inverter easily handles my well pump start surge of over 4000W, yet would blow fuses trying to start that 2400W step down transformer, so be aware of the potentially huge inrush currents of high efficiency core toroidal transformers.  It sure surprised me and had me scratching my head until I measured the peak current and then did some technical reading. 

The ST-3 never had any issues starting the 2400W step down transformers, so I had been blissfully unaware of this issue.  Some toroidal transformers use core material designed to minimize this problem, and in my inverter development I started with a 120V output, and had unknowingly used some surplus 1100W transformers that were of that type.  When I first switched to new Antek transformers, for which I had rewound the secondaries, I had an "educational experience" with loud bang and smoke coming out of my electronics! By starting them on alternating polarity, very short pulses, gradually increasing in width, they could be essentially degaussed from their last operation and started up with no problem.  (Most electronic transformer soft starters use this method.)

I know the Stamford heads have zero problems with split phase, imbalanced load operation, need no work on bearings, diode bridge or voltage regulation.  Gary at DES recommended them many years ago and all reports have been the same; no problems at alll.  Alas, they don't have a small one and the price was over my budget.

Thanks for filling us in on your engine and genhead details.  That's a whole other story; it's nice that you can ignore Listerflicker.  Using the harmonic for excitation should be fine in this case.  Just remember you can always use the mains for excitation later if the harmonic should fail.  As for harmonic hump distortion I have no experience with the St-10.  If you have or can borrow even the cheapest of ocilloscopes to get us a picture of your output waveform, that will give us a good idea of what should be done.  There are some very cheap, handheld digital o'scopes out there perfectly adequate for much troubleshooting/checkout work.  Single trace, even 1 MHz bandwidth will do the job; I use one for most of my own design and troubleshooting, except where bench testing requires my PICOscope.  My dual trace analog/CRT scope just gathers dust.

I concur fully with your decision to experiment to see if this ST-10 will handle split phase, to avoid transformer cost and losses if possible.  You might also see if the stock harmonic with rheostat is adequate for your range of loads on this setup.  It may very well be, and if so, I'd stick with that over the known to be less than durable cheap AVR's from China or CGG.  If you need the AVR for your loads,  get a spare if buying the China cheap one (same as CGG).  About 3 years of regular daily use is all you should expect.  On Ebay or elsewhere, you're looking for ST-10 brush generator head compatibility.  

One other issue is the regulation of the two legs of 120V when using an AVR.  If your head can handle split phase, mismatched 120V loads, just be aware that regulation per leg may get a bit sloppy.  I think the 230V regulator is best, which works similarly to the Harmonic regulation; the average of the two 120V legs will be right, at least.  If using a 120V AVR that is regulating based on one lightly loaded leg, and you put a very large load on the other, you could have a motor burnout low voltage situation on one leg. With ST heads and India's Listeroids/Clones, it's best to assume nothing and test/inspect everything  Both are very useful, affordable gear for very handy skeptics.

+1 on both current transformer and bridge diode replacement with metal bodied, modern one.  Some thermal grease or silicone caulk in a pinch on the connection to some metal sheet surface is advised.  I like to bolt through sheet, into a finned aluminum heatsink where practical, both with a thin coat of thermal grease.

Hey DieselfuelOnly,
Good question, but some more info is needed, though I can make some general suggesti9ns.  You didn't mention the engine, rpm, or ST head size, or whether your setup was 120, 230, or split phase 120/240. Those do make a difference.

Waveform distortions vary dramatically between different ST heads, since manufacturers have varied over the years.  For many applications and specific gen heads that may not be important. Voltage regulation via harmonic with a rheostat or adjustable resistor can be acceptable for many applications too.  Harmonic regulation will in fact handle large, low power factor loads much better than the typical affordable AVR, which does NOT regulate to true RMS volrtage. 

For AVR configuration, many ST3 and  ST5 heads will groan and make vibration noises if imbalanced by running spilt phase loads, or putting an AVR on one leg of a split phase setup.  I suggest avoiding that.  In fact I suggest avoiding split phase setups for these heads entirely.  The 230/240V rated unit sold by CGG in the past will minimize flicker best if installed with the mains only as excitation.  That will eliminate the "harmonic hump" distortion that is pretty band on some ST3 and ST5 heads.  The reason to use the mains is this:  the harmonic wiinding puts out more volts when there is a load, and on my ST3 I have measured the peak voltage at over 400V for starting a 1.5 HP equivalent motor.  It is just 4 skinny spikes per rotation, however, so when compression stroke comes and rpm slows down, so does the harmonic output.  If you put an AVR  using the Harmonic winding as excitation, it can only limit the output of the harmonic.  So for ST heads with properly wound harmonic windings, you are only limiting and already limiited output, and the mains voltage will sag.  If you use the mains for excitation, especially with the 240V AVR, you have some serious head room for the AVR to work with and it will partially correct the voltage sag of the compression stroke.  Either approach will improve the voltage rise during the power stroke. 

For most utility uses like running pumps and motors and tools,  there's little need for precise voltage regulation or worry about Listerflicker.

I hope that helps explain things.  I've been inside 5 -ST-3's and designed my own AVR electronics. A long time ago I offered a flicker reducing AVR plan as open source, and have thus seen oscilliscope shots of a few ST-3's ST-5's and a couple ST-7's.  Some have acceptable waveform distortion, the worst have such bad ratcheting around the peaks that I wouldn't run them myself.  With lots of distortion, some mechanical timers will groan and get hot, and motors will get a bit hotter and be less efficient, power wise.  A good AVR set up will reduce flicker as much as SOM type flywheels, and I've also posted that comparison publicly.  AVR flicker reduction is reduced as the head gets larger, because of the lag of larger inductance in the larger excitation coils.

My neighbor is running a CGG ST-3 with a cheap China 230V AVR.   It works well, but he keeps a spare on hand as they typically fail every 2-3 years, though he does put on perhaps 600 hrs/year.  They are similar to the units CGG sells, he was out of 230V at the time.  We tried to use the 120V AVR CGG sent with it but it made the ST set up as 230VAC moan from the small load imbalance.   I have also not been impressed with the quality of newer ST heads-  harmonic windings are so wrong (very high voltage and no rheostat)  that they can't be used without an AVR, and we got a head with aluminum rotor windings that failed open in 6 months.

My ST-3 on a homebrew AVR has been very reliable.  If I've got to run something  with a nasty PF like a small MIG welder, I flip a switch to go back to harmonic.
Bruce






The huge variation explains why some think ST heads are fine, while others really suffer. 

The induction generator is self syncing when doing grid backfeed, you just increase rpm slightly above operating rpm and watch the backfeed current as you pour on the power.  Much cleaner and simpler setup for you, better efficiency.  No load specific capacitors needed for this application, and it automatically stops when power shuts off. 

Using a big choke as the first stage of filtering (BEFORE capacitor) requires what is known as ''critical inductance''.  You can google that and find the equation.  Other than that, you just need a choke rated for at least your max current.  20,000 uF and 5 mH will probably be adequate.

3 phase would be vastly better for making DC, and would require a smaller choke and less capacitance.  Depending on the inverter, nothing but a 3 phase rectifier may be needed (6 diodes).

I've read about the cyclic loading from MPPT inverters which Glort refers too, but have no first hand experience to be able to suggest solutions beyond the one he suggests which effectively bypasses any MPPT hunting.  The problem he reports I've read of several times from different sources.

Glort will have some words with you when I list this about BC power rates:

Under the Residential Conservation Rate, customers pay 8.58 cents per kWh for the first 1,350 kWh they use over an average two-month billing period. Above that amount, customers pay 12.87 cents per kWh for the balance of the electricity used during the billing period.

Canadians have it pretty soft if BC Hydro lets you store up back feed credits for use 6 months later!  They must be zinging you with a ferocious monthly fee or I can't see how they can manage.  Otherwise you have a free battery service, in effect.  Sweet for you if true.  

Be aware that trying to slam huge amounts of power directly into capacitors as is done for  small power supplies is going to give you crap power factor, meaning fuses/breakers popping or generator windings fried.  Instead, use a choke filter, around 5 mH, as the first element.  That will restore your PF and smooth out the current waveform. It's going to be a monster, though.  Gapped toroidal transformer cores make nice chokes for this purpose and any of the custom transformer shops can make one for you.  Hamilton makes big power  E-I cored chokes of this sort also, and you can occasionally find them used on ebay. 

Using ICE to generate heat is a lot of moving parts to maintain for what could be done more efficiently and with far fewer parts with a good burner, and some like the Babington can burn any kind of oil.  You aren't the first to attempt this, even on this forum, but the operating cost of using an engine as a heater is not going to work out well economically.  The exhaust heat is about 1/3 of the total and is a PITA to collect due to service/maintenance issues. 

A fun project though, certainly.